Which of the following characterizes monumental structure building in the Nuraghi culture of Sardinia?

The characteristic that best describes monumental structure building in the Nuraghi culture of Sardinia is:

**Evidence of high levels of cooperation needed to build castle-like structures.**

The construction of the Nuraghi, which are distinctive stone towers, suggests that communities worked together and had organized efforts to create these monumental structures, indicating a common goal and purpose in their building projects.